Java 休眠 - org.hibernate.exception.GenericJDBCException：无法打开连接
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时间：2020-08-14 01:17:34 来源:igfitidea点击:
Hibernate - org.hibernate.exception.GenericJDBCException: Cannot open connection
提问by Suvo
In order to solve the issue of too many connections to DB and idle connections, we made the following changes to the Configuration file-
为了解决DB连接过多和空闲连接过多的问题，我们对Configuration文件做了如下改动——
c3p0.min_size=1
c3p0.max_size=20
c3p0.timeout=1800
c3p0.max_statements=50
connection.release_mode=on_close
After that, while trying to run the application, we are getting the following exception. Please advice why this is happening & how this can be corrected -
之后，在尝试运行应用程序时，我们收到以下异常。请建议为什么会发生这种情况以及如何纠正 -
HTTP Status 500 - org.hibernate.exception.GenericJDBCException: Cannot open connection
type Exception report
输入异常报告
message org.hibernate.exception.GenericJDBCException: Cannot open connection
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: org.hibernate.exception.GenericJDBCException: Cannot open connection
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:286)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause
org.hibernate.exception.GenericJDBCException: Cannot open connection
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
org.hibernate.loader.Loader.doQuery(Loader.java:696)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
org.hibernate.loader.Loader.doList(Loader.java:2232)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
org.hibernate.loader.Loader.list(Loader.java:2124)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
com.alci.common.LoginAction.login(LoginAction.java:127)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause
java.sql.SQLException: Connections could not be acquired from the underlying database!
com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
org.hibernate.loader.Loader.doQuery(Loader.java:696)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
org.hibernate.loader.Loader.doList(Loader.java:2232)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
org.hibernate.loader.Loader.list(Loader.java:2124)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
com.alci.common.LoginAction.login(LoginAction.java:127)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
root cause
com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577)
org.hibernate.loader.Loader.doQuery(Loader.java:696)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
org.hibernate.loader.Loader.doList(Loader.java:2232)
org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
org.hibernate.loader.Loader.list(Loader.java:2124)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363)
org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
com.alci.common.LoginAction.login(LoginAction.java:127)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.alci.filters.ParamFilter.doFilter(ParamFilter.java:27)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.36 logs.
回答by Vlad Mihalcea
You ran out of database connections.
您用完了数据库连接。
This means two things:
这意味着两件事：
- Your transaction take too much time because of slow queries so a connection is being held for way too much time
- You have very high traffic demands which can't fit into a 20 connections pool size.
- 由于查询缓慢，您的事务花费了太多时间，因此连接被保持的时间太长
- 您有非常高的流量需求，无法容纳 20 个连接池大小。
I recommend you read the following read my answer of this SO question.
我建议您阅读以下内容，阅读我对此问题的回答。
I don't think this settings is recommended:
connection.release_mode=on_close
ON_CLOSE - is essentially the legacy behavior described above. The Hibernate session obtains a connection when it first needs to perform some JDBC access and holds unto that connection until the session is closed.
on_close - says to use ConnectionReleaseMode.ON_CLOSE. This setting is left for backwards compatibility, but its use is highly discouraged.
ON_CLOSE - 本质上是上述的遗留行为。Hibernate 会话在第一次需要执行某些 JDBC 访问时获取连接并保持该连接直到会话关闭。
on_close - 说使用 ConnectionReleaseMode.ON_CLOSE。保留此设置是为了向后兼容，但强烈建议不要使用它。
Try using "auto" instead.
尝试改用“自动”。
回答by Nazeer Syed
This sometimes arises due to timeout. Increase the timeout and it will hopefully resolve the issue.
这有时是由于超时而出现的。增加超时时间，它有望解决问题。
c3p0.timeout=6000
